TY - JOUR
T1 - Calcium Carbonate-Modified Surfaces by Electrocrystallization to Study Anionic Surfactant Adsorption
AU - Liu, Zilong
AU - Onay, Hayati
AU - Guo, Fengzhi
AU - Chen, Junqing
AU - Poltorak, Lukasz
AU - Hedayati, Pegah
AU - Sudhölter, Ernst J.R.
PY - 2021
Y1 - 2021
N2 - In view of enhanced oil recovery, the adsorption behavior of surfactants is usually monitored on smooth model rock surfaces using quartz crystal microbalance with dissipation (QCM-D). However, this is an impractical situation as the effect of the surface roughness of reservoir rocks and its role in surfactant adsorption processes are not yet completely understood. The coupling of electrochemical techniques and QCM-D in one analysis setup (EQCM-D) provides a new methodology to explore complex surfactant adsorption processes. In this work, a uniform, rough, and well-covered model CaCO3 surface was obtained on gold and platinum sensors to model carbonate rocks. This was achieved by the electrochemically formed hydroxide ions in the presence of bicarbonate and calcium ions, by which the controlled deposition of CaCO3 resulted in sensor surface coverages in the range 35-40%. Before using the deposited CaCO3 surfaces, the adsorption of anionic surfactant alcohol alkoxy sulfate (AAS) on a smooth commercially available CaCO3 surface was studied with varying CaCl2 concentrations. For the first time, the structure and characteristics of the formed AAS layer were quantitatively described, indicating the formation of an incomplete bilayer. Compared to the smooth CaCO3 surface, an increase in the frequency shift from 5 to 15 times was observed in sensors covered with rough CaCO3 deposit. This observation was primarily attributed to the rougher surfaces that possess more adsorption sites for AAS binding and also to the effect of liquid trapping, inducing additional frequency shifts. The obtained results show that surfactant adsorption on rough surfaces was vastly different from that on smooth surfaces, and they provide a better understanding of the adsorption behavior of surfactants to mineral surfaces.
AB - In view of enhanced oil recovery, the adsorption behavior of surfactants is usually monitored on smooth model rock surfaces using quartz crystal microbalance with dissipation (QCM-D). However, this is an impractical situation as the effect of the surface roughness of reservoir rocks and its role in surfactant adsorption processes are not yet completely understood. The coupling of electrochemical techniques and QCM-D in one analysis setup (EQCM-D) provides a new methodology to explore complex surfactant adsorption processes. In this work, a uniform, rough, and well-covered model CaCO3 surface was obtained on gold and platinum sensors to model carbonate rocks. This was achieved by the electrochemically formed hydroxide ions in the presence of bicarbonate and calcium ions, by which the controlled deposition of CaCO3 resulted in sensor surface coverages in the range 35-40%. Before using the deposited CaCO3 surfaces, the adsorption of anionic surfactant alcohol alkoxy sulfate (AAS) on a smooth commercially available CaCO3 surface was studied with varying CaCl2 concentrations. For the first time, the structure and characteristics of the formed AAS layer were quantitatively described, indicating the formation of an incomplete bilayer. Compared to the smooth CaCO3 surface, an increase in the frequency shift from 5 to 15 times was observed in sensors covered with rough CaCO3 deposit. This observation was primarily attributed to the rougher surfaces that possess more adsorption sites for AAS binding and also to the effect of liquid trapping, inducing additional frequency shifts. The obtained results show that surfactant adsorption on rough surfaces was vastly different from that on smooth surfaces, and they provide a better understanding of the adsorption behavior of surfactants to mineral surfaces.
UR - http://www.scopus.com/inward/record.url?scp=85100208829&partnerID=8YFLogxK
U2 - 10.1021/acs.energyfuels.0c03695
DO - 10.1021/acs.energyfuels.0c03695
M3 - Article
AN - SCOPUS:85100208829
SN - 0887-0624
VL - 35
SP - 1358
EP - 1370
JO - Energy and Fuels
JF - Energy and Fuels
IS - 2
ER -